Example 3.1. The maximum demand on a power station is 100 MW. Ifthe annual load factor is 40% , calculate the total energy generated in a year. Example 3.2. A generating station has a connected load of 43MW and a maximum demand of 20 MW: the units generated being 61:5 x 10° per annum. Calculate (i) the demand factor and (ii) load factor. Example 3.3. A 100 MW power station delivers 100 MW for 2 hours, 50 MW for 6 hours and is shut down for the rest of each day. It is also shut down for maintenance for 45 days each year. Calculate its annual load factor. Example 3.4. A generating station has a maximum demand of 25MW, a load factor of 60%. a plant capacity factor of 50% and a plant use factor of 72%. Find (i) the reserve capacity of the plant (i) the daity energy produced and (iti) maximum energy that could be produced daily if the plant while running as per schedule, were fully loaded. Example 3.5. A diesel station supplies the following loads to various consumers © Industrial consumer = 1500 kW ; Commercial establishment = 750 kW Domestic power = 100 kW; Domestic light = 450kW If the maximum demand on the station is 2500 kW and the number of kWh generated per year is 45 x 10°, determine (i) the diversity factor and (ii) annual load factor. Example 3.6. A power station has a maximum demand of 15000 kW. The annual load factor is 50% and plant capacity factor is 40%. Determine the reserve capacity of the plant. Example 3.7. A power supply is having the following loads = Type of load ‘Max. demand (&W) Diversity of group Demand factor Domestic 41500 12 os Commercial 2000 “I 09 Industrial 10,000 125 7 If the overall system diversity factor is 1-35, determine (i) the maximum demand and (ii) con nected load of each type. Example 3.9. 1s has been desired to install a diesel power station to supply power tna suburban area having the following particulars © (1000 houses with average connected load of 1-5 KW in each house. The demand factor and diversity factor being On and 25 reapectivels. (i) 10 factories having overall maximum demand of 90 kW. (ii) 7 ubewells of 7 KW each and operating together in the morning. The diversity factor among above three types of consumers is 1-2. What should be the mininnim capacity of power station > Example 3.10. A generating station has the following daily load eyele : Time (Hours) 0—6 6—10 10-12 1216 16-20 2024 Load (MW) 4050 oo so 70 40 Draw the load curve and find () maxinum demand (ii) units generated per day (iil) average joad and iv) load factorExample 3.11. A power station has to meet the following demand : Group A: 200 kW between 8 A.M. and 6 P.M. Group B : 100kW between 6 A.M. and 10 A.M. Group C > SOkW berween 6A.M. and 10 A.M. Group D + 100 kW between 10 A.M. and 6 PM. and then between 6 PM. and 6 A.M. Plot the daily load curve and determine (i) diversity factor (ii) units generated per day (iil) load factor. Time ‘Consumer 1 Consumer 2 Consumer 3 12 midnight 10 8AM. ‘No toad 200w ‘No toad BAM. 102 PM. coow No toad 200 Ww 2PM. 104 PM. 200W 1000 W 1200W 4PM. 10 10 PM. s00w No toad No load OPM. to midnight No toad 200W 200W Fes the Saad Gonree aad find Ct toslonsa Aoamaced af atlvtdinad earner toad Gastar af inetivtcal iit) diveraiey fixctor and (iv) lonad factor of the station. Example 3.13. A daily load curve which exhibited a 15-minute peak of 3000 kW is drawn to scale of I.em = 2 hours and I cm = 1000 kW. The total area under the load curve is measured by (pameiestias aa eee arb oe Ce coe atid ceva oe Sects Example 3.14, A power station has a daily load cycle as under : 260 MW for 6 hours : 200 MW for 8 hours : 160 MW for 4 hours, 100 MW for 6 hours. If the power station is equipped with 4 sets of 75 MW each. calculate (i) daity load factor (ii) plant capacity factor and (ii) daily requirement if the calorific value of oil used were 10,000 kcal/kg. ‘and the average heat rate of station were 2860 keal/KWh. ‘Example 3.16. The annual load duration curve of a certain power station can be considered as a straight line from 20 MW to-4 MW. Tomeet this load. three turbine-generator units, two rated at 10 MW each and one rated at 5 MW are installed. Determine (i) installed capacity (ti) plant factor (ti) units generated per annum (iv) load factor and (v) utilisation factor. TUTORIAL PROBLEMS ‘A generating station has a connected load of 40 MW and a maximum demand of 20 MW : the units Sencrated being 60 10". Calculate () the demand factor (A the load factor os a Se25%0) 2. A100 MW powers stations delivers 100 MW for 2 hours, 50 MW for # hours and is shut down for the festor each day It is also shut down for maintenance for 60 days cach Year Calculate its annual Hood factor Taser 3. A power station is to supply four regions of loads whose peak values are 10,000 kW, S000 kW, 8000 kW ‘and 7000 KW. "The diversity factor of the load at the station is 1S and the average annual load factor i= 60%. Calculate the maximum demand on the station and annual energy supplied from the station. [20,000 KW ; 105-12 x 10 kWh} 4. A generating station supplies the following loads : 15000 kW. 12000 kW, 8500 kW. 6000 kW and 450| KW. The station has a maximum demand of 22000 kW. The annual load factor of the station ix 48%. Calculate () the number of units supplied annually (#/) the diversity factor and (ii) the demand factor [() 925 x 10" kWh tif) S2-4% (it) 19) S.A generating station has a maximum demand of 20 MW. a load factor of 60%. a plant capacity factor of 4%0 and a plant wee Factor of 30% - Find = (® the daily enerey produced Gd the reserve capacity of the plant6. A generating station has the following daily load cycle = “Time (hours) 06 610 10—12 1216 16-20 20-24 Load Mw) 20 23 30 23 35 20 Draw the load curve and find @) maximum demand, Gd) units generated per day. (id average load. 0) toad factor, 1G) 35 MW (di) $60 % 10° KW (iit) 23888 RW Civ) 66-67%) 7. A power station has to meet the following load demand : Load A SOkW between 10 AM. and 6 PM. Load B 30kW between 6PM. and 10 PM. Load € 20kW between 4PM. and 10 A.M. Plot the daily load curve and determine (i) diversity factor (ji) units generated per day (iii) load factor. [@) 1-43 (id) 880 KWh (iit) 52-38%) 8. A substation supplies power by four feeders to its consumers. Feeder no. 1 supplies six consumers whose individual daily maximum demands are 70 kW, 90 kW, 20 kW, 50 kW, 10 kW and 20 kW while the maximum demand on the feeder is 200 kW. Feeder no. 2 supplies four consumers whose daily ‘maximum demands are 60 kW, 40 kW, 70 kW and 30 kW, while the maximum demand on the feeder is 160 KW. Feeder nos. 3 and 4 have a daily maximum demand of 150 kW and 200 kW respectively while the maximum demand on the station is 600 kW. Determine the diversity factors for feeder no. 1. feeder no. 2 and for the four feeders. [1-3, 1-25, 1-183] 9 Accentral station is supplying energy to a community through two substations. Each substation feeds four feeders. The maximum daily recorded demands are : POWER STATION....... 12,000 KW ‘Sub-station B .... 9000 kW Feeder 1 2820 kW Feeder 2 1800 kW Feeder 3 4000 kW Feeder 4 .. 600 kW Feeder 4 2900 kW Calculate the diversity factor between (i) substations (i/) feeders on substation A and (iii) feeders on sub- station B. [@ 1-25 Gi) 1-15 Git) 1-24) 10, The yearly load duration curve of a certain power station can be approximated as a straight line ; the ‘maximum and minimum loads being 80 MW and 40 MW respectively. To meet this load, three turbine- {generator units, two rated at 20 MW each and one at 10 MW are installed. Determine (i) installed ‘capacity (ji) plant factor (iii) kWh output per year (iv) load. factor. EE) SONMIW (i) 48% Gili) 2100 6 VO (iv) 6AM